The usual procedure for producing printed materials and primarily for producing newspaper print in which each page includes several columns and photographs and different printed articles, in contrast to the printed usual page of a book, involves making a paste-up in which the actual printed articles and photographs are individually arranged on and secured to a grid board in the desired location and arrangement as would appear the printed page. This paste-up as it is referred to in the printing industry, is then photographed by a camera which makes a negative of the paste-up. This negative then is registered with a negative working plate, usually in a vacuum frame for exposure, and the exposed plate is processed and ready for press. These negative working plates are usually extremely precision sheets of special metal having a finely controlled thickness and coating on one side thereof. Although these negative working plates are used and perform satisfactory in the printing industry they are relatively expensive due to the coating that is applied thereto.
It would be desirable for ease of production and economy to use a positive working plate in contrast to the currently used negative plates. Positive plates would eliminate the photographing of the paste-up board prior to registering it with a positive working plate. However, prior coaters used for coating positive plates for use in the printing industry are expensive due to the precision rollers and bearing arrangements therefor and the difficulty of controlling the coating applied since a very precision coating is required on the plates. Although positive working offset plates have been developed for use in the printing industry they are used mainly for high quality printing such as books, in contrast to use in a lower quality printing of the type used for newspapers due to the cost of the plates.
Accordingly, the need has existed particularly for use in the printing industry for a coating device which can apply a precision coating to a positive-working offset plate intended for use primarily in the newspaper industry. There is no known coating device of which I am aware which achieves these results.